You can also use a image instead of a ``real'' filesystem, for example on FreeBSD:
First create a image, 100MB in this case:
$ dd if=/dev/zero of=secret.img bs=1024K count=100
Next use mdconfig to create a /dev entry:
# mdconfig -at vnode -f secret.img
Next you can follow the normal stept for creating an encrypted filesystem (i.e. Killasmurf's FreeBSD + Geli
), using md0.
You can use
# mdconfig -du0
to detach the device.
This is much more flexible and faster, and you can set it up any time, no need to newfs stuff ...